> ## Documentation Index
> Fetch the complete documentation index at: https://docs.arcium.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Solana integration: orchestration and execution

> How Arcium uses Solana for onchain coordination, node management, and payment processing

The Arcium Network uses Solana to orchestrate and manage computational workflows efficiently. Solana's high throughput and low latency enable Arcium's core processes, such as computation orchestration, node management, and payment systems, to operate onchain.

### Onchain coordination

The Arcium Network uses Solana-based programs to coordinate the following key processes:

* **Node Management**: Registration, configuration, and scheduling of Arx nodes, ensuring they are ready to process tasks securely.
* **Computation Orchestration**: Collecting computations into per-Cluster mempools, assigning tasks to Clusters of Arx nodes, and processing results.
* **Network Economics**: Managing charges, rewards, staking, and epoch settlement.

Arx nodes execute computations offchain, while Solana coordinates accounts, queues, payments, and callbacks. Each computation is queued in its Cluster's **onchain mempool** and executed by that Cluster's Arx nodes.

### Mempool architecture

To efficiently manage computations, **each Cluster maintains its own mempool**, where commissioned computations for that Cluster's MPC eXecution Environments (MXEs) are queued and prioritized for execution. Priority-fee ordering is scoped to the Cluster's mempool, so computations compete only with others queued for the same Cluster.

Once a computation enters the mempool:

* It awaits execution by the Cluster's Arx nodes. When a valid leader choice is available, it can take one dispatch slot; otherwise priority-fee and account-lock ordering apply. See [Leader weight](/staking/overview#leader-weight).
* Queued computations have a 180-slot mempool TTL. If a computation is still `Queued` and has not been promoted for execution after expiry, the payer can reclaim its computation fee.
* The Cluster bound to the MXE executes the computation.

This keeps queue competition local to the Cluster while combining stake-weighted leader selection with customer-selected priority prices.

### Workflow execution

Once queued, computations are:

1. **Collected** in the mempool.
2. **Promoted** for execution by the Cluster bound to the computation's MXE.
3. **Finalized** through the configured success or failure callback.

Solana coordinates accounts, queues, payments, and callbacks. Arx nodes execute the MPC computation offchain, and the callback authenticates the Cluster-signed outcome.


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